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This is the most visited page on my website, and I wish to thank you for your visit.  I invite you to link to some of the other topics beyond geology that I write about on my blog, JackHassard.org.  Here some other pages that you might like to visit:

The Trump Files: This is my recent book is an in-depth exploration of the tumultuous years of Donald Trump’s administration. It dives deep into how American democracy, human rights, science, and public health have been affected by his presidency. From controversial decisions to far-reaching consequences for the world, this book provides insight into the inner workings of the White House. With vivid detail and gripping accounts, The Trump Files offers a comprehensive look at one of the most consequential presidencies in US history.

The Climate Threat: This is a selection of posts that I’ve written about climate change and existential threat climate change poses to life on earth.

The Nuclear Threat: This is a series of posts on the nuclear threat. 

COVID-19: Explored in detail in The Trump Files, here you find a few posts about origins and prevention of pathogens.

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Thank you.  Now onto plate tectonics and the theory of gravity. 

Plate tectonics is the central and unifying theory of geology. 

Plate Tectonics has been an interest of mine for a long time ever since I was in graduate school in the late 60s.  In 1969, I began my university teaching and research career at Georgia State University.  I started off teaching geology courses for teachers in the Atlanta area, and began to introduce plate tectonics into these courses.  In 1972,  I was visiting professor of science education at Florida State University as a researcher and writer.   One of my projects was to revise Crusty Problems,  a middle school science text.  It was one of the texts of the Intermediate Science Curriculum Study (ISCS), a curriculum for middle school science.  My interest in plate tectonics, geology and writing science texts converged in Tallahassee.

 Plate Tectonics

You must remember that plate tectonics theory was just emerging from the work of geologists from the 50s through the mid 1970s.   I studied geology as part of my Ph.D program at The Ohio State University in the late 1960’s.   J. Tuzo Wilson was on leave during one of the years I was taking geology courses at OSU.  He offered a seminar on plate tectonics for doctoral students, which I attended.  Professor Wilson was a Canadian geophysicist and geologist who achieved worldwide acclaim for his contributions to the theory of plate tectonics.  Most geologists rejected ideas of continents and plates moving prior to the 1970s.  Here is an interesting part of Wilson’s history with the theory of plate tectonics and publishing.

His theory that volcanic island chains may have formed due to the movement of a plate over a stationary ‘hotspot’ in the mantle was so controversial that his paper was rejected by all major international scientific journals.  It wasn’t until 1963 that it was finally published in the Canadian Journal of Physics.  In 1965 he published a paper that introduced the concept of the transform fault.  This theory became one of the bases for plate tectonics.

Wilson’s ideas had a great influence on my career of teaching and writing about geology.  The opportunity to re-write a middle school geology text was a wonderful opportunity.

It was my desire to include plate tectonics in the text I was revising. The initial manuscript had nothing about continental drift, sea floor spreading or plate tectonics.   I designed a sea floor spreading activity to illustrate one aspect of plate tectonics.  Professor Harry Hess, of Princeton University, outlined a theory that could explain how the continents could actually drift.   This theory later became known as ‘Sea Floor Spreading’.  Hess believed that ocean trenches were the locations where ocean floor was destroyed and recycled.  The activity I developed was a hands on visualization of ocean spreading in opposite directions from the mid-ocean ridges. 

At the time,  plate tectonics was a new idea. Now we know the earth’s crust is  broken into huge plates.  Much of the action is along the interfaces between the plates. When we study the seismicity of the earth, we detect the pattern of earthquakes that follows the interfaces between the various major and minor tectonic plates.  The sea floor spreading activity I designed illustrated two plates spreading apart.

Figure 1. Seafloor spreading

Figure 2. Map of Plate Tectonics along the Mid-Ocean Ridge

Plate Tectonics Timeline

• 1596. Flemish cartographer & mapmaker Abraham Ortelius noted coastlines of the continents appear to fit together.  He suggested the Americas were torn away from Europe and Africa.  He proposed the idea of continental drift.  Probably the first to do so.
• 1912. German meteorologist and geophysicist Alfred Wegener proposed the continents were once joined in a supercontinent called Pangea.  He suggested that portions of the supercontinent moved thousands of miles apart of millions of years via a process he called “continental displacement (continental drift).  Most geologists dismissed the idea because Wegener could not identify a force to drive the continents.
• 1929. Arthur Holmes, a British geologist proposed that convection in the mantle is the force driving continental drift. Again, his ideas was not accepted by many, but much later his theory gained support.
• 1950s. Ocean going vessels mapping the ocean floor provided data about the features of the ocean basin, including the discovery of mid-ocean ridges.
• 1951-1953. Marie Tharp and Bruce Heezen did topographical research plotting ship data to discover the presence of a mid-ocean rift valley along the axis of the Mid-Ocean Ridge causing a paradigm shift leading to the acceptance of sea floor spreading and plate tectonics. When Marie Tharp showed Heezen that her plotting of the North Atlantic revealed a rift valley, Heezen dismissed it as “girl talk”. She persisted and they eventually discovered that not only was there a North Atlantic rift valley, but a mountain range with a central valley that spanned the earth.  They also realized that the oceanic earthquakes they had been separately plotting fell within the rift, a revolutionary theory at the time.  He presented this mid-ocean rift and earthquake theory at Princeton in 1957.  At that lecture, preeminent geologist Harry Hess told Heezen, “You have shaken the foundations of geology!” 
• Shown below is a painting of the Mid-Ocean Ridge by Heinrich Berann (1977) based on the scientific profiles of Marie Tharp and Bruce Heezen.  
• 
• 1960. American geophysicist Harry H. Hess developed idea that oceanic crust forms along mid-ocean ridges, based on the research of Marie Tharp and Bruce Heezen.  
• 1961. Geophysicist Robert S. Dietz named the Hess process “sea floor spreading.”  Hess and Dietz led the way to the theory of plate tectonics.
• 1963. British and Canadian geologists working independently suggested that the new crust would have a magnetization aligned with the Earth’s geomagnetic field. They noted this would exist over geologic time as bands of crust that exhibit alternating patterns of magnetic polarity. Later such patterns were identified.
• Mid to late 1960s.  Global network of sensors to monitor the Nuclear Test-Ban Treaty of 1963 revealed earthquakes and volcanic activity occur almost exclusively at the edges of tectonic plates.
• 1965. Symposium at the Royal Society of London on continental drift marked the beginning of the acceptance of plate tectonics theory.
• 1965. J. Tuzo Wilson, who promoted sea floor spreading and continental drift added the idea of transform faults to the theory, completing the classes of fault types needed for the plates to move.  Wilson then published a paper describing a cycle of continental break up, formation of an ocean basin between the broken plates, followed by convergence where two continental plates (blocks) collide.  This is the Wilson cycle.
• 1967. W. Jason Morgan proposed the Earth’s surface consists of 12 plates that move relative to each other.
• 1968. Dan McKenzie, Professor of Geophysics at the University of Cambridge proposed the Theory of Plate Tectonics.

Figure 3. Tectonic Activity

There is little disagreement within the scientific community about the viability of plate tectonics.  There might be more disagreement over gravity, however.

Pros & Cons of Science Theories

Not so clever politicians are trying to stir things up for science teachers.  They are passing bills that require teachers to discuss the pro’s and con’s of science theories.  These include evolution, global warming, and human cloning.  It might not make sense to some to discuss the advantages & disadvantages  of plate tectonics & gravity, but politicians in Kentucky, Louisiana, Texas, and South Dakota might consider it an important teaching strategy.  As I traced the history of plate tectonics, note that the theory described what scientists had discovered about the Earth’s crust.  The theory of plate tectonics was not a wild guess.  Although it took time for geologists to accept ideas like continental drift, acceptance was based on data, on information.  Once the theory of plate tectonics was seen as a valid explanation of the earth’s crust and its movements, there was really on one side to the theory.  Having a debate on the pros and cons of Plate Tectonics doesn’t make any sense.  Well, unless you are a legislator.

Here is how legislators in Kentucky put it in an Act relating to science education and intellectual freedom

• Teachers, principals, and other school administrators are encouraged to create and foster an environment within public elementary and secondary schools that promotes critical thinking skills, logical analysis, and open and objective discussion of the advantages and disadvantages of scientific theories being studied.
• After a teacher has taught the content related to scientific theories contained in textbooks and instructional materials included on the approved lists required under KRS 156.433 and 156.435, a teacher may use, as permitted by the local school board, other instructional materials to help students understand, analyze, critique, and review scientific theories in an objective manner, including but not limited to the study of evolution, the origins of life, global warming, and human cloning.
• This section shall not be construed to promote any religious doctrine, promote discrimination for or against a particular set of religious beliefs, or promote discrimination for or against religion or no religion.

You’ll notice the Act did not include the theories of plate tectonics or gravity.  However, the Act did expect teachers, after they have taught evolution, global warming, or human cloning, to stop, and have a discussion of the advantages and disadvantages of these theories. Teachers are told to discuss pro’s & con’s of science theories.  Balanced treatment!

Figure 4. The Theory of Plate Tectonics Describes & Predicts Large Scale Motions of the Earth’s Crust

If you examine the “act” or “bills” from different states, they use the same language.  They couch their demands by encouraging teachers to teach critical thinking.

But in reality it is simply another way for the same group that tried to insist that “intelligent design (ID)” is science, and should be taught along with evolution.

The case against intelligent design was decided in the Dover, PA case ruled on by Judge John Jones in December 2005. In the verdict, the Judge ruled that ID is not science.  As a result ID is not to be taught in science class to preserve the separation of church and state, among other things. Now, proponents of teaching the  advantages and disadvantages of a science theory are trying to come in the back door by insisting that “both” sides of a theory be discussed.  Again, teachers are told discuss pro’s & con’s of science theories.

Both Sides of a Theory?

The problem is that scientific ideas do not necessarily have two sides. Yet you would not believe it by watching the media.  To the media, all issues have two sides. With the use of split screen technology, the media presents to the public a “balanced” treatment of the issue. In his book on climate change, Stephen H. Schneider, the tactic of “balanced treatment” actually becomes the tactic of “persistent distortion.” He puts it this way:

One of the key reasons for distortion in the media reports on climate change is perceived need for “balance” in journalism (substitute science teaching for journalism, and you have the logic behind these efforts to discuss pro’s and con’s of a theory). In reporting political, legal, or other advocacy-dominated stories, it is appropriate for journalists to report both sides of an issue. Got the democratic view? Better get the Republican.

In science, the situation is radically different. There are rarely just two polar-opposite sides, but rather a spectrum of potential outcomes, which are often accompanied by a history of scientific assessment of the relative-credibility of each possibility.

Schneider addresses the issue and problem with the pro/con approach to a scientific idea, especially one like climate change (or evolution or human cloning). And in his statement he shows us how this approach to exploring scientific ideas leaves us with nothing more than two sides squaring off against each other:

Being stereotyped as the “pro” advocate (advantages of—name your theory) versus the “con” advocate as far as action on climate change is concerned is not a quick ticket to a healthy scientific reputation as an objective interpreter of the science—particularly for a controversial science like climate change, which rarely one-sided. In actuality, it encourages personal attacks and distortions. This all part of the problem I call, somewhat whimsically, “mediarology.”

Scientific theories are abstract and conceptual, and to this end they are never right or wrong. Instead, they are supported or challenged by observations in the real world. The American Association for the Advancement of Science advances our understanding of scientific theories when they say:

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not “guesses” but reliable accounts of the real world. The theory of biological evolution is more than “just a theory.” It is as factual an explanation of the universe as the atomic theory of matter or the germ theory of disease. Our understanding of gravity is still a work in progress. But the phenomenon of gravity, like evolution, is an accepted fact.

In a climate of polarization and partisanship, the school science curriculum could become the playing field of the same group that advocated equal time for creation science, and the inclusion of intelligent design in science teaching. As Leslie Kaufman suggests in a New York Times article, “Darwin foes add warming to target.” In the article Kaufman points out that:

Critics of the teaching of evolution in the nation’s classrooms are gaining ground in some states by linking the issue to global warming, arguing that dissenting views on both scientific subjects should be taught in public schools.

Theories to Consider

To be true to the suggestion of exploring the advantages and disadvantages of scientific theories, teachers might be told to discuss the pro’s & con’s of  science theories.  Of course, what we know is that we should be helping students understand these theories, and that requires critical thinking.